How long does it take a 750W heater to raise the temperature of 1kg of water from 20oC to 50oC [specific heat capacity of water = 4200Jkg-1K-1]

Answer Details

To calculate the time it takes for a 750W heater to raise the temperature of 1kg of water from 20°C to 50°C, we can use the formula: Q = mcΔT where Q is the heat energy required to heat up the water, m is the mass of water, c is the specific heat capacity of water, and ΔT is the change in temperature. Solving for Q, we get: Q = mcΔT Q = 1kg x 4200J/kg°C x (50°C - 20°C) Q = 126000J Now, we can use the formula for power to find out how long it takes for the heater to produce 126000J of heat energy: P = E/t t = E/P where P is the power of the heater, E is the energy produced by the heater, and t is the time taken. Solving for t, we get: t = E/P t = 126000J / 750W t = 168 seconds Therefore, the answer is 168s.